In the general state of the art of electrical and electronic systems housed in cabinets (often termed chassis), there are typically inputs and outputs to the system, facilitated by connection of communication links of various sorts, over which signals are received and sent. There are also numerous situations wherein groups of components in a chassis have to be connected to and communicate with other groups of components internally. Data routers in packet networks, such as the well-known Internet, are a good example. In description in this specification a data router is used as a specific example of such a situation, and the present invention in several aspects is applicable to such routers.
Transmission of network data traffic is accomplished with the use of data routers as introduced above. A physical data routing machine typically consists of a processing unit or multiple units which are housed in a chassis and which communicate with each other and with other data routing machines.
In prior art, one method for achieving communication between processing units in a single chassis, such as in a data router, involves the use of an electrical backplane. When communication between multiple chassis is required, cables have been used to connect the electrical backplanes of the chassis. The electrical backplane is commonly implemented as a printed circuit board assembly, which provides electrical connectivity between processing units.
Noting that it may sometimes be desirable to communicate at backplane level between elements that are not closely physically associated, such as between elements that may be mounted in separate physical electronic cabinets, there is a potential problem with electrical backplanes. When an electrical signal is transmitted over relatively long distances, for example, deterioration of the signal may occur for any of several reasons. For example, longer signal paths necessarily present additional resistance. Also, longer paths present additional opportunity for interference. Therefore, in order to transmit clean signals in systems utilizing electrical backplanes, the elements in communication must be in relatively close physical proximity to one another, such as in the same cabinet.
Another drawback to electrical backplane boards is that they are relatively difficult to service. One reason is that the conductors for the electrical signals are typically patterned on the board, and individual conductors (signal paths) cannot be separately serviced. In many cases the backplane boards are also hardwired to other components. Because any change or repair is normally via a replacement of the entire backplane, the system containing the electrical backplane is generally out of service during any backplane service.
A modular and adjustable backplane assembly is known to the inventor, and is taught in the patent application referenced as a priority document in the Cross-Reference section above. The assembly provides a fiber-optics backplane interface to a plurality of router cards functioning as a data router. The modular assembly has a first portion housing a first array of connector halves for interfacing with a compatible array of connector halves mounted to specified router cards. The assembly also has a second portion having a second array of connector halves for interfacing with a compatible array of connector halves specific to another type of router card used in the same router. The mechanics of the assembly enable a moveable backplane attachment with respect to the first and second portions of the assembly such that they may be positionally adjusted during mounting, and wherein external data paths are provided from individual ones of the connectors to individual others of the connectors by fiber-optic conductors. The backplane assembly is illustrated in FIGS. 1 and 2 herein, and the adjustment capability is illustrated in FIG. 2 of the co-pending application.
In the above-referenced backplane assembly, each connector housing comprises a male and female component (halves) that snap together. Referring to FIG. 1 of Ser. No. 09/920,556, only the backplane connector halves LC and FC connectors 103 and 102 respectively are illustrated. Each component contains at least 4 separate fiber optic contact inserts provided in the form of spring-loaded inserts, also termed ferrules by the inventor, that when inserted properly and with the connector housing snapped together, provide the actual fiber optic interface. Each springloaded insert or ferrule has a connector head, a snap-in body, and a spring bridging the former components to provide flexibility in alignment. The entire assembly fits over a fiber optic cable set and presents the fiber optics cable ends in a strategic array. Two opposing ferrules in proper position complete a fiber-optics channel. The connector heads of the backplane inserts contain the contact surface portions which must be kept clean to provide a good fiber optics connection. As is well known in the art, particulate matter collecting on the contact surfaces of a fiber optics ferrule can seriously degrade transmission performance.
In current art, the fabric cards and line cards (FC,LC) of the router connect to the backplane assembly through the router chassis utilizing the housing connector components to align and retain the multiple opposing inserts that actually form the transmission connections (See FIG. 3). Each router card has mounted thereon an array of one type (male or female) housing components. Currently on one type of card (FC) there are 5 such housing components retaining 4 each of the contact inserts. Therefore, there are 20 separate inserts or ferrules per card that interface with a same number of inserts or ferrules in the backplane assembly whose contact surfaces must be kept free of particulate matter.
Current cleaning practices require that a card first be removed from its shelf (unplugged) so that the associated backplane contact surfaces are then accessible for cleaning. Each component housing retaining the inserts on the backplane has a spring-loaded, hinged door that covers the contact surfaces of its housed inserts collectively and protects those surfaces from dust and other particulate matter when a card is not plugged in to the assembly. The door swings positively toward the inside of the housing and inserts when pushed on. When the housing components are snapped together, the door is in the open position.
A cleaning tool for cleaning particulates from a single connector surface is available to the inventor. This tool has a handle extension and a profile that allows the cleaning portion of the tool to extend through the small space in a card shelf left by a removed card. The tool must be inserted through the space and through the door of the component housing on the backplane in order to reach the contact surface to be cleaned. Because the component housings are vertically stacked (typically 5) on the backplane assembly, an adjustment mechanism with an extension is provided to elevate the cleaning tool to the proper height profile of each insert contact surface to be cleaned. Adjustments must be made each time one surface is cleaned.
What is clearly needed is a mechanism for cleaning optics contact surfaces on a backplane assembly that can clean all of the surface areas comprising a connection between a router card and a backplane assembly simultaneously or at least much more efficiently than cleaning one surface at a time between height adjustments. A mechanism such as this would greatly reduce downtime to a router connection due to cleaning.